body {
  width: 100vw;
  height: 100vh;
  /* background-color: black; */
  margin: 0;
  padding: 0;

  font-family:
    Helvetica Neue,
    Helvetica,
    PingFang SC,
    Hiragino Sans GB,
    Microsoft YaHei,
    Arial,
    sans-serif;
}

aside,
section,
main,
header,
div {
  box-sizing: border-box;
}
.floatleft {
  float: left;
}

.floatright {
  float: right;
}

.clear {
  clear: both;
}
